The DECam Legacy Survey (DECaLS)
has announced its third data release. An NOAO Survey Program led by
co-PIs David Schlegel (LBNL) and Arjun Dey (NOAO), DECaLS uses the Dark
Energy Camera (DECam) on the CTIO Blanco 4m telescope to image nearly
square degrees of the extragalactic sky in three bands (g, r and z).
Earlier data releases were made in June 2015 (DR1) and February 2016
(DR2). The current status of the survey is shown here.

The third data release (DR3), which covers [4300, 4600, 8100] square
degrees in [g, r, z] bands respectively, includes catalogs and images
obtained between August 2014 and March 2016. DR3 also incorporates
public data within the DECaLS footprint from other NOAO observing
programs and photometry from NASA’s Wide-Field Infrared Surveyor’s maps
of the sky.

The final DECaLS sky coverage will extend in declination from
approximately -18 to +30 degrees, and cover Galactic latitudes |b| >
18 degrees. The survey also overlaps the SDSS/BOSS extragalactic
footprint. DECaLS will allow astronomers to probe the structure of the
Milky Way, the nature of dark energy, and many other topics in
astrophysics. All data are immediately non-proprietary and the project
schedules two data releases per year.

DECaLS is one of three surveys that will jointly image 14,000 square
degrees—nearly one-third of the sky—to provide targets for the Dark
Energy Spectroscopic Instrument cosmology project. The other two
projects are the Mayall z-band Legacy Survey (MzLS), which began in
February 2016, and the Beijing-Arizona Sky Survey (BASS), currently
underway at the Bok Telescope on Kitt Peak. MzLS and BASS will provide
g- ,r-, and z- band imaging at declinations north of +34 degrees.

DECaLS DR3 data products are available through the NOAO Science Archive and ftp server.
In addition, the NOAO Data Lab has developed a database to query all
DR3 catalogs, which is available by contacting the Data Lab directly (datalab@noao.edu).

Contact UsYour input is welcome on any of these issues. Please send your thoughts to:currents@noao.edu.